The toxicity of certain foods that contain high amounts of vitamin A has been recognized for centuries.

The 1597 diary of Gerrit de Veer, which he wrote while taking refuge in the winter in Nova Zembla during an attempt to reach Indonesia by the northern passage, states that he and his men became gravely ill after eating polar-bear liver. They feared for their lives but ultimately recovered. De Veer's diary also notes widespread and striking desquamation during recovery.1

Vitamin A — retinol — is present in food sources such as liver, kidney, and milk. Dairy foods are fortified with small . . .